/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * This file is part of the TinyUSB stack.
 */

#include "tusb_option.h"

#if (CFG_TUD_ENABLED && CFG_TUD_CDC)

#include "device/usbd.h"
#include "device/usbd_pvt.h"
#include "cdc_device.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF
//--------------------------------------------------------------------+
enum {
    BULK_PACKET_SIZE = (TUD_OPT_HIGH_SPEED ? 512 : 64)
};

typedef struct
{
    uint8_t itf_num;
    uint8_t ep_notif;
    uint8_t ep_in;
    uint8_t ep_out;

    // Bit 0:  DTR (Data Terminal Ready), Bit 1: RTS (Request to Send)
    uint8_t line_state;

    /*------------- From this point, data is not cleared by bus reset -------------*/
    char wanted_char;
    cdc_line_coding_t line_coding;

    // FIFO
    tu_fifo_t rx_ff;
    tu_fifo_t tx_ff;

    uint8_t rx_ff_buf[CFG_TUD_CDC_RX_BUFSIZE]; // RX FIFO
    uint8_t tx_ff_buf[CFG_TUD_CDC_TX_BUFSIZE]; // TX FIFO

#if CFG_FIFO_MUTEX
    osal_mutex_def_t rx_ff_mutex;
    osal_mutex_def_t tx_ff_mutex;
#endif

    // Endpoint Transfer buffer
    CFG_TUSB_MEM_ALIGN uint8_t epout_buf[CFG_TUD_CDC_EP_BUFSIZE];
    CFG_TUSB_MEM_ALIGN uint8_t epin_buf[CFG_TUD_CDC_EP_BUFSIZE];

} cdcd_interface_t;

#define ITF_MEM_RESET_SIZE offsetof(cdcd_interface_t, wanted_char)

//--------------------------------------------------------------------+
// INTERNAL OBJECT & FUNCTION DECLARATION
//--------------------------------------------------------------------+
CFG_TUSB_MEM_SECTION static cdcd_interface_t _cdcd_itf[CFG_TUD_CDC];

static bool _prep_out_transaction(cdcd_interface_t* p_cdc)
{
    uint8_t const rhport = 0;
    uint16_t available = tu_fifo_remaining(&p_cdc->rx_ff);

    // Prepare for incoming data but only allow what we can store in the ring buffer.
    // TODO Actually we can still carry out the transfer, keeping count of received bytes
    // and slowly move it to the FIFO when read().
    // This pre-check reduces endpoint claiming
    TU_VERIFY(available >= sizeof(p_cdc->epout_buf));

    // claim endpoint
    TU_VERIFY(usbd_edpt_claim(rhport, p_cdc->ep_out));

    // fifo can be changed before endpoint is claimed
    available = tu_fifo_remaining(&p_cdc->rx_ff);

    if (available >= sizeof(p_cdc->epout_buf)) {
        return usbd_edpt_xfer(rhport, p_cdc->ep_out, p_cdc->epout_buf, sizeof(p_cdc->epout_buf));
    } else {
        // Release endpoint since we don't make any transfer
        usbd_edpt_release(rhport, p_cdc->ep_out);

        return false;
    }
}

//--------------------------------------------------------------------+
// APPLICATION API
//--------------------------------------------------------------------+
bool tud_cdc_n_connected(uint8_t itf)
{
    // DTR (bit 0) active  is considered as connected
    return tud_ready() && tu_bit_test(_cdcd_itf[itf].line_state, 0);
}

uint8_t tud_cdc_n_get_line_state(uint8_t itf)
{
    return _cdcd_itf[itf].line_state;
}

void tud_cdc_n_get_line_coding(uint8_t itf, cdc_line_coding_t* coding)
{
    (*coding) = _cdcd_itf[itf].line_coding;
}

/**
 * @brief 设置要监听的字符
 *
 * @param itf
 * @param wanted
 */
void tud_cdc_n_set_wanted_char(uint8_t itf, char wanted)
{
    _cdcd_itf[itf].wanted_char = wanted;
}

//--------------------------------------------------------------------+
// READ API
//--------------------------------------------------------------------+
uint32_t tud_cdc_n_available(uint8_t itf)
{
    return tu_fifo_count(&_cdcd_itf[itf].rx_ff);
}

/**
 * @brief 外部调用 读取接收到的数据
 *
 * @param itf
 * @param buffer
 * @param bufsize
 * @return uint32_t
 */
uint32_t tud_cdc_n_read(uint8_t itf, void* buffer, uint32_t bufsize)
{
    cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
    uint32_t num_read = tu_fifo_read_n(&p_cdc->rx_ff, buffer, (uint16_t)bufsize);
    _prep_out_transaction(p_cdc);
    return num_read;
}

bool tud_cdc_n_peek(uint8_t itf, uint8_t* chr)
{
    return tu_fifo_peek(&_cdcd_itf[itf].rx_ff, chr);
}

void tud_cdc_n_read_flush(uint8_t itf)
{
    cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
    tu_fifo_clear(&p_cdc->rx_ff);
    _prep_out_transaction(p_cdc);
}

//--------------------------------------------------------------------+
// WRITE API
//--------------------------------------------------------------------+
uint32_t tud_cdc_n_write(uint8_t itf, void const* buffer, uint32_t bufsize)
{
    cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
    uint16_t ret = tu_fifo_write_n(&p_cdc->tx_ff, buffer, (uint16_t)bufsize);

    // flush if queue more than packet size
    if (tu_fifo_count(&p_cdc->tx_ff) >= BULK_PACKET_SIZE) {
        tud_cdc_n_write_flush(itf);
    }

    return ret;
}

uint32_t tud_cdc_n_write_flush(uint8_t itf)
{
    cdcd_interface_t* p_cdc = &_cdcd_itf[itf];

    // Skip if usb is not ready yet
    TU_VERIFY(tud_ready(), 0);

    // No data to send
    if (!tu_fifo_count(&p_cdc->tx_ff))
        return 0;

    uint8_t const rhport = 0;

    // Claim the endpoint
    TU_VERIFY(usbd_edpt_claim(rhport, p_cdc->ep_in), 0);

    // Pull data from FIFO
    uint16_t const count = tu_fifo_read_n(&p_cdc->tx_ff, p_cdc->epin_buf, sizeof(p_cdc->epin_buf));

    if (count) {
        TU_ASSERT(usbd_edpt_xfer(rhport, p_cdc->ep_in, p_cdc->epin_buf, count), 0);
        return count;
    } else {
        // Release endpoint since we don't make any transfer
        // Note: data is dropped if terminal is not connected
        usbd_edpt_release(rhport, p_cdc->ep_in);
        return 0;
    }
}

uint32_t tud_cdc_n_write_available(uint8_t itf)
{
    return tu_fifo_remaining(&_cdcd_itf[itf].tx_ff);
}

bool tud_cdc_n_write_clear(uint8_t itf)
{
    return tu_fifo_clear(&_cdcd_itf[itf].tx_ff);
}

/**
 * @brief CDC驱动初始化
 *
 */
void cdcd_init(void)
{
    tu_memclr(_cdcd_itf, sizeof(_cdcd_itf));
    for (uint8_t i = 0; i < CFG_TUD_CDC; i++) {
        cdcd_interface_t* p_cdc = &_cdcd_itf[i];

        p_cdc->wanted_char = (char)-1;

        // 初始化默认的串口参数
        p_cdc->line_coding.bit_rate = 115200;
        p_cdc->line_coding.stop_bits = 0;
        p_cdc->line_coding.parity = 0;
        p_cdc->line_coding.data_bits = 8;

        // 配置接收FIFO
        tu_fifo_config(&p_cdc->rx_ff, p_cdc->rx_ff_buf, TU_ARRAY_SIZE(p_cdc->rx_ff_buf), 1, false);

        // Config TX fifo as overwritable at initialization and will be changed to non-overwritable
        // if terminal supports DTR bit. Without DTR we do not know if data is actually polled by terminal.
        // In this way, the most current data is prioritized.
        tu_fifo_config(&p_cdc->tx_ff, p_cdc->tx_ff_buf, TU_ARRAY_SIZE(p_cdc->tx_ff_buf), 1, true);

#if CFG_FIFO_MUTEX
        tu_fifo_config_mutex(&p_cdc->rx_ff, NULL, osal_mutex_create(&p_cdc->rx_ff_mutex));
        tu_fifo_config_mutex(&p_cdc->tx_ff, osal_mutex_create(&p_cdc->tx_ff_mutex), NULL);
#endif
    }
}

void cdcd_reset(uint8_t rhport)
{
    (void)rhport;

    for (uint8_t i = 0; i < CFG_TUD_CDC; i++) {
        cdcd_interface_t* p_cdc = &_cdcd_itf[i];

        tu_memclr(p_cdc, ITF_MEM_RESET_SIZE);
        tu_fifo_clear(&p_cdc->rx_ff);
        tu_fifo_clear(&p_cdc->tx_ff);
        tu_fifo_set_overwritable(&p_cdc->tx_ff, true);
    }
}

uint16_t cdcd_open(uint8_t rhport, tusb_desc_interface_t const* itf_desc, uint16_t max_len)
{
    // Only support ACM subclass
    TU_VERIFY(TUSB_CLASS_CDC == itf_desc->bInterfaceClass && CDC_COMM_SUBCLASS_ABSTRACT_CONTROL_MODEL == itf_desc->bInterfaceSubClass, 0);

    // Find available interface
    cdcd_interface_t* p_cdc = NULL;
    for (uint8_t cdc_id = 0; cdc_id < CFG_TUD_CDC; cdc_id++) {
        if (_cdcd_itf[cdc_id].ep_in == 0) {
            p_cdc = &_cdcd_itf[cdc_id];
            break;
        }
    }
    TU_ASSERT(p_cdc, 0);

    //------------- Control Interface -------------//
    p_cdc->itf_num = itf_desc->bInterfaceNumber;

    uint16_t drv_len = sizeof(tusb_desc_interface_t);
    uint8_t const* p_desc = tu_desc_next(itf_desc);

    // Communication Functional Descriptors
    while (TUSB_DESC_CS_INTERFACE == tu_desc_type(p_desc) && drv_len <= max_len) {
        drv_len += tu_desc_len(p_desc);
        p_desc = tu_desc_next(p_desc);
    }

    if (TUSB_DESC_ENDPOINT == tu_desc_type(p_desc)) {
        // notification endpoint
        tusb_desc_endpoint_t const* desc_ep = (tusb_desc_endpoint_t const*)p_desc;

        TU_ASSERT(usbd_edpt_open(rhport, desc_ep), 0);
        p_cdc->ep_notif = desc_ep->bEndpointAddress;

        drv_len += tu_desc_len(p_desc);
        p_desc = tu_desc_next(p_desc);
    }

    //------------- Data Interface (if any) -------------//
    if ((TUSB_DESC_INTERFACE == tu_desc_type(p_desc)) && (TUSB_CLASS_CDC_DATA == ((tusb_desc_interface_t const*)p_desc)->bInterfaceClass)) {
        // next to endpoint descriptor
        drv_len += tu_desc_len(p_desc);
        p_desc = tu_desc_next(p_desc);

        // Open endpoint pair
        TU_ASSERT(usbd_open_edpt_pair(rhport, p_desc, 2, TUSB_XFER_BULK, &p_cdc->ep_out, &p_cdc->ep_in), 0);

        drv_len += 2 * sizeof(tusb_desc_endpoint_t);
    }

    // Prepare for incoming data
    _prep_out_transaction(p_cdc);

    return drv_len;
}

// Invoked when a control transfer occurred on an interface of this class
// Driver response accordingly to the request and the transfer stage (setup/data/ack)
// return false to stall control endpoint (e.g unsupported request)
bool cdcd_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const* request)
{
    // Handle class request only
    TU_VERIFY(request->bmRequestType_bit.type == TUSB_REQ_TYPE_CLASS);

    uint8_t itf = 0;
    cdcd_interface_t* p_cdc = _cdcd_itf;

    // Identify which interface to use
    for (;; itf++, p_cdc++) {
        if (itf >= TU_ARRAY_SIZE(_cdcd_itf))
            return false;

        if (p_cdc->itf_num == request->wIndex)
            break;
    }

    switch (request->bRequest) {
    case CDC_REQUEST_SET_LINE_CODING:
        if (stage == CONTROL_STAGE_SETUP) {
            TU_LOG2("  Set Line Coding\r\n");
            tud_control_xfer(rhport, request, &p_cdc->line_coding, sizeof(cdc_line_coding_t));
        } else if (stage == CONTROL_STAGE_ACK) {
            if (tud_cdc_line_coding_cb)
                tud_cdc_line_coding_cb(itf, &p_cdc->line_coding);
        }
        break;

    case CDC_REQUEST_GET_LINE_CODING:
        if (stage == CONTROL_STAGE_SETUP) {
            TU_LOG2("  Get Line Coding\r\n");
            tud_control_xfer(rhport, request, &p_cdc->line_coding, sizeof(cdc_line_coding_t));
        }
        break;

    case CDC_REQUEST_SET_CONTROL_LINE_STATE:
        if (stage == CONTROL_STAGE_SETUP) {
            tud_control_status(rhport, request);
        } else if (stage == CONTROL_STAGE_ACK) {
            // CDC PSTN v1.2 section 6.3.12
            // Bit 0: Indicates if DTE is present or not.
            //        This signal corresponds to V.24 signal 108/2 and RS-232 signal DTR (Data Terminal Ready)
            // Bit 1: Carrier control for half-duplex modems.
            //        This signal corresponds to V.24 signal 105 and RS-232 signal RTS (Request to Send)
            bool const dtr = tu_bit_test(request->wValue, 0);
            bool const rts = tu_bit_test(request->wValue, 1);

            p_cdc->line_state = (uint8_t)request->wValue;

            // Disable fifo overwriting if DTR bit is set
            tu_fifo_set_overwritable(&p_cdc->tx_ff, !dtr);

            TU_LOG2("  Set Control Line State: DTR = %d, RTS = %d\r\n", dtr, rts);

            // Invoke callback
            if (tud_cdc_line_state_cb)
                tud_cdc_line_state_cb(itf, dtr, rts);
        }
        break;
    case CDC_REQUEST_SEND_BREAK:
        if (stage == CONTROL_STAGE_SETUP) {
            tud_control_status(rhport, request);
        } else if (stage == CONTROL_STAGE_ACK) {
            TU_LOG2("  Send Break\r\n");
            if (tud_cdc_send_break_cb)
                tud_cdc_send_break_cb(itf, request->wValue);
        }
        break;

    default:
        return false; // stall unsupported request
    }

    return true;
}

/**
 * @brief 接收到数据
 *
 * @param rhport
 * @param ep_addr
 * @param result
 * @param xferred_bytes 传输字节
 * @return true
 * @return false
 */
bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
{
    (void)result;

    uint8_t itf;
    cdcd_interface_t* p_cdc;

    // Identify which interface to use
    for (itf = 0; itf < CFG_TUD_CDC; itf++) {
        p_cdc = &_cdcd_itf[itf];
        if ((ep_addr == p_cdc->ep_out) || (ep_addr == p_cdc->ep_in))
            break;
    }
    TU_ASSERT(itf < CFG_TUD_CDC);

    // Received new data
    if (ep_addr == p_cdc->ep_out) {
        // 接收到新数据, 写入到FIFO缓冲中
        tu_fifo_write_n(&p_cdc->rx_ff, &p_cdc->epout_buf, (uint16_t)xferred_bytes);

        // 检查需要的字符并在匹配时调用 tud_cdc_rx_wanted_cb函数
        if (tud_cdc_rx_wanted_cb && (((signed char)p_cdc->wanted_char) != -1)) {
            for (uint32_t i = 0; i < xferred_bytes; i++) {
                if ((p_cdc->wanted_char == p_cdc->epout_buf[i]) && !tu_fifo_empty(&p_cdc->rx_ff)) {
                    tud_cdc_rx_wanted_cb(itf, p_cdc->wanted_char);
                }
            }
        }

        // 调用接收回调（如果仍有数据）
        if (tud_cdc_rx_cb && !tu_fifo_empty(&p_cdc->rx_ff))
            tud_cdc_rx_cb(itf);

        // prepare for OUT transaction
        _prep_out_transaction(p_cdc);
    }

    // Data sent to host, we continue to fetch from tx fifo to send.
    // Note: This will cause incorrect baudrate set in line coding.
    //       Though maybe the baudrate is not really important !!!
    if (ep_addr == p_cdc->ep_in) {
        // invoke transmit callback to possibly refill tx fifo
        if (tud_cdc_tx_complete_cb)
            tud_cdc_tx_complete_cb(itf);

        if (0 == tud_cdc_n_write_flush(itf)) {
            // If there is no data left, a ZLP should be sent if
            // xferred_bytes is multiple of EP Packet size and not zero
            if (!tu_fifo_count(&p_cdc->tx_ff) && xferred_bytes && (0 == (xferred_bytes & (BULK_PACKET_SIZE - 1)))) {
                if (usbd_edpt_claim(rhport, p_cdc->ep_in)) {
                    usbd_edpt_xfer(rhport, p_cdc->ep_in, NULL, 0);
                }
            }
        }
    }

    // nothing to do with notif endpoint for now

    return true;
}

#endif
